The present invention relates to an urging device, including a multiple loading member that employ springs for urging, at multiples, a member displaced by an external force, and relates to a paper feeding device, including the urging device, that is used for a recording apparatus, such as a printer.
In general, mechanisms employing springs are frequently used to provide mechanical control for devices, for example, for urging mechanical components in a specific direction. Spring urging members having such a function are frequently used for recording apparatuses, such as facsimile machines, copiers and printers. As an example, for a paper feeding device used in a recording apparatus, a paper cassette in which a plurality of sheets are stacked is generally used, and spring urging member is employed for an edge guide mechanism that aligns the side edge of the paper stacked in the cassette.
For the printing of data by a recording apparatus equipped with a paper cassette, sheets are fed individually; successive topmost sheets stacked in the paper cassette are intermittently stripped off by feeding rollers and supplied to immediately adjacent conveying rollers, which carry the sheets to the recording head. To perform high quality printing, since the rotation of the paper feeding rollers and the conveying rollers must be controlled precisely, a DC motor and a stepping motor are employed, and a trailing paper edge pushing member is provided for the paper cassette. The trailing paper edge pushing member pushes against the trailing edge of a sheet, or an edge guide member, to align a side edge and ensure that the top sheet is separated and surely fed.
A demand exists for a structure having a different spring urging mechanism that is designed for use with a wide variety of products; a practical, general purpose device that can be manufactured at a low cost. For the mechanism of a paper supply device for pushing against and aligning the side edges of paper, a sufficient pressing force is required to accurately align and maintain the alignment of the paper edges. But too much force should not be applied in this instance, because force exceeding that required for alignment is converted into a load and is applied to the paper feeding and conveying rollers during the paper supply process. If, however, too little pressing force is applied, paper edges are aligned less accurately and the edge guide effect is reduced, and the paper tends to be fed obliquely. It should be further noted that it is not preferable for pressing force to be exerted against the side edges of paper during the paper feeding process; this force is converted into a load and is imposed on the drive motor.
Structures wherein users are required to position paper side edges manually are commonly used. However, since such an operation is tedious and, depending on the user, the positioning of the paper will differ slightly each time it is performed, this requirement tends to aggravate the above problem.
It is one objective of the present invention to provide an urging device, incorporating a multiple loading member, that facilitates the design of an urging mechanism for utilizing the loading member, and that is suitable for widespread employment for general purpose applications.
It is another objective of the present invention to provide a paper feeding device that employs the urging device as a mechanism for the alignment and the maintenance of the alignment of the side edges of sheets stacked in a paper cassette.
It is an additional objective of the present invention to provide a reliable paper feeding device that reduces the number of paper cassette related operations required of users, thereby removing differences attributable to user performance of paper cassette related operations, and that improves the performance of the paper cassette paper setting function.
In order to achieve the above objects, according to the present invention, there is provided an urging device, comprising:
a deforming member, being deformable in accordance with an external force;
a multiple load applier, provided with a plurality of loading members each having an urging ability, for applying an urging force which is generated as a resultant urging force derived from at least one loading member selected from the plural loading members,
wherein the number of selected loading member is multiply changed in accordance with the deformation amount of the deforming member.
In this configuration, a desired urging force can be exerted against the target by an arbitrary combination composed of plural loading members.
Preferably, the plural loading members include at least two loading members whose urging abilities are different from each other.
In this configuration, even when the deformation amount of the deforming member is unchanged, a change in the resultant urging force can be effected.
Preferably, a predetermined deformation amount of the deforming member is associated with each of the loading member. Each of the loading members has no urging ability when the deformation amount of the deforming member is less than the associated predetermined deforming amount.
In this configuration, an arbitrary urging force can be easily generated by the selection of available loading member.
Preferably, the deformation of the deforming member is established by a cam and a cam follower.
In this configuration, the sequence for providing the load is assigned for a function of the cam, so that a transient urging force change can be applied to the target.
According to the invention, there is also provided a paper feeding device, comprising:
a cassette member, in which sheets to be fed are stacked;
a side edge aligner, provided in the cassette member so as to be adjacent to side edges of the stacked sheets;
a plurality of loading members, being deformable so as to respectively provide an urging force to the side edge aligner, such that the side edge aligner aligns the side edges of the stacked sheets at a predetermined position; and
a load controller, for deforming the loading members such that a resultant urging force applied to the side edge aligner is multiply varied.
In this configuration, since the necessary pressing force can be exerted only when the side edges of the sheets are aligned, to feed a sheet from the paper cassette, while reducing the drive load imposed on the paper feed rollers, the pressure is reduced so as to maintain only the state wherein the side edges of the sheets are aligned.
Here, it is preferable that the loading members provide the resultant urging force such that the side edge aligner is separable from the side edges of the stacked sheets.
In this configuration, since the resultant urging force exerted by the loading members is concentrated on the side edges of the sheets, the side edges can be efficiently aligned by the application of a minimum load.
Here, it is preferable that the side edge aligner includes a pair of arm members which are almost linearly arranged. Further ends of the arm members are pivotably supported by the cassette member, and closer ends thereof are coupled with the loading members.
In this configuration, since the resultant urging force is concentrated substantially in the middle in the side edges of the paper, the side edges of the paper can be efficiently aligned by the application of a minimum urging force.
Here, it is preferable that the feeding device further comprises.
an urging member for urging the movable plate toward a first direction which is opposed to the aligning movement of the side edge aligner; and
a stopper for preventing the movable plate from moving toward the first direction.
Here, the movable plate holds the side edge aligner at a position which is separated from the side edges of the stacked sheets, when the movement of the movable plate is restricted by the stopper.
In this configuration, when the cassette member is removed, i.e., when the cassette member is not attached, no load is imposed on the side edge aligner, and therefore, the side edge aligner does not interfere with the stacking of sheets, and the supplementation of the supply of sheets can be performed efficiently.
Preferably, the load controller includes a movable plate whose displacement amount is associated with the resultant urging force of the loading members. A predetermined displacement amount of the movable plate is associated with each of the loading member. Each of the loading members has no urging ability when the displacement amount of the movable plate is less than the associated predetermined displacement amount.
In this configuration, in accordance with the sheet size stacked in the cassette member, an arbitrary urging force can be easily generated by the selection of the loading member.
Here, it is preferable that each of the loading member is provided with an engagement member. Each of the respective engagement members is placed within a slot which is formed in the movable plate, and which extends in a movable direction of the movable plate. Each of the respective engagement member engages with the associated slot when the displacement amount of the movable plate exceeds the associated predetermined displacement amount.
In this configuration, since normally the slots and the ends of the individual loading members have different shapes, an arbitrary urging force can be easily generated by the selection of slots, and of loading members that have end shapes corresponding to the slots.
Preferably, the paper feeding device further comprises:
a cassette holder, to which the cassette member is detachably inserted; and
a cooperation mechanism for associating an insertion movement of the cassette member with the movement of the movable plate.
In this configuration, after a cassette member has been inserted, the side edges of the sheets are aligned, so that handling of sheets relative to the cassette member can be improved.
Here, it is preferable that the cooperation mechanism includes a boss provided between the movable plate and the cassette member, and a cam groove in which the boss is moved in accordance with the insertion movement.
In this configuration, the side edges of the sheets can be accurately aligned, and oblique feeding due to the non-alignment of sheets, can be prevented.
Preferably, the paper feeding device further comprising a cassette holder, to which the cassette member is detachably inserted. The loading members include at least two loading members whose urging abilities are different from each other. The load controller deforms weaker loading member in an initial stage and a final stage of the insertion operation of the cassette member. The load controller deforms both of weaker and stronger loading members when the side edge aligner aligns the side edges of the stacked sheets.
In this configuration, since a large pressing force is required for the side edge alignment while only a small pressing force is required to maintain the aligned state of the side edges of the sheets, these suited pressing forces can be easily generated.
According to the invention, there is also provided a paper feeding device, comprising:
a cassette member, in which sheets to be fed are stacked;
a side edge aligner, provided in the cassette member so as to be adjacent to side edges of the stacked sheets, the side edge aligner including a first load acting member and a second load acting member;
a movable member, being movable with respect to the side edge aligner, the movable member including a first load application member and a second load application member;
a first elastic member, deformably connected between the first load application member and the first load acting member; and
a second elastic member, deformably connected between the second load application member and the second load acting member.
Here, no load is applied on the first and second load application members, when a distance between the movable member and the side edge aligner is a first distance. A first load is applied on the first load application member, and a first urging force for urging the side edge aligner toward the side edges of the stacked sheets acts on the first load acting member, when the distance between the movable member and the side edge aligner increases from the first distance by L1. A second load is applied on the second load application member, and a second urging force acts on the second load acting member in addition to the first urging force, when the movable member is moved so that the distance between the movable member and the side edge aligner increases from the first distance by L2 (L2 greater than L1).
In this configuration, the degree of alignment, produced by the increased pressure applied to the side edges of the sheets, is gradually increased.
Preferably, the first and second load acting members are provided as first and second slots extending in a movable direction of the movable member, respectively. The first elastic member is a tension spring, one end of which is formed with a hook member hooked over the first slot with a clearance L1, and the other end of which is fixed to the first load acting member. The second elastic member is a tension spring, one end of which is formed with a hook member hooked over the second slot with a clearance L2, and the other end of which is fixed to the second load acting member.
In this configuration, when the movable member is shifted, the clearance L1 at the end of the first tension spring is removed and the end engages with the first slot, so that the first tension spring is extended. Since the clearance L2 is larger than the clearance L1, as the shifting of the movable member continues, the second tension spring is subsequently extended. Therefore, the urging force that impels the side edge aligner and presses it against the side edges of the sheets is respectively and gradually increased in accordance with the distance traveled by the movable member.
Alternatively, the first and second load acting members are provided as first and second slots extending in a movable direction of the movable member, respectively. The first elastic member is a tension spring, one end of which is formed with a hook member hooked over the first slot with a clearance L1, and the other end of which is fixed to the first load application member. The second elastic member is a tension spring, one end of which is formed with a hook member hooked over the second slot with a clearance L2, and the other end of which is fixed to the second load application member.
Alternatively, the first and second load application members are provided as first and second slots extending in a movable direction of the movable member, respectively. The first and second load acting members are provided as third and fourth slots extending in a movable direction of the movable member, respectively. The first elastic member is a tension spring, one end of which is formed with a hook member hooked over the first slot, and the other end of which is formed with a hook member hooked over the third slot. The second elastic member is a tension spring, one end of which is formed with a hook member hooked over the second slot, and the other end of which is formed with a hook member hooked over the fourth slot. An additional clearance between the both hook members and the associated slots in the first elastic member is L1. An additional clearance between the both hook members and the associated slots in the second elastic member is L2.
Preferably, the paper feeding device further comprises a cassette holder, to which the cassette member is detachably inserted. The movable member is moved such that only the first urging force is applied to the side edge aligner, then the second urging force is added to the first urging force, and then only the first urging force is applied again, in accordance with the inserting operation of the cassette member.
In this configuration, an increasing load is gradually imposed when the side edges of the sheets are aligned. Then, the load imposed by the elastic members is gradually reduced. Thus, the pressure applied to the side edges of the sheets is reduced while the aligned state of the sheets is maintained and the resistance is reduced when a sheet is fed from the cassette member.
According to the invention, there is also provided a paper feeding device, comprising:
a cassette member, in which sheets to be fed are stacked;
a side edge aligner, provided in the cassette member so as to be adjacent to side edges of the stacked sheets, the side edge aligner including first to n-th load acting members;
a movable member, being movable with respect to the side edge aligner, the movable member including first to n-th load application members; and
first to n-th first elastic members, deformably connected between the first to n-th load application members and the first to n-th load acting members, respectively.
Here, n is an integer which is 3 or more. No load is applied on the first to n-th load application members, when a distance between the movable member and the side edge aligner is a first distance. First to n-th loads are applied on the first to n-th load application members, and first to n-th urging forces for urging the side edge aligner toward the side edges of the stacked sheets act on the first to n-th load acting members in order, when the distance between the movable member and the side edge aligner increases from the first distance by L1, L2 . . . Ln (L1 less than L2 less than  . . .  less than Ln).
In this configuration, when the first to n-th elastic members are extended in the named order, in accordance with the distance of the movable member travels, a greater load is gradually impose on the side edge aligner. Therefore, the side edge aligner is impelled toward the side edges of the sheets by a steadily increasing force, and the degree of alignment, produced by the pressure applied to the side edges of the sheets, is gradually increased.
Preferably, the first to n-th load acting members are provided as first to n-th slots extending in a movable direction of the movable member, respectively. The first to n-th elastic member are tension springs, one ends of which are formed with hook members respectively hooked over the first to n-th slots with clearances L1, L2, . . . Ln, and the other ends of which are fixed to the first to n-th load acting members.
In this configuration, when the movable member is shifted, the clearance L1 at the end of the first tension spring is removed and the end engages with the first slot, so that the first tension spring is extended. Since the clearance lengths L1 to Ln increase in numerical order, as the shifting of the movable member continues, the clearances of the tension springs are removed and the springs are extended in order, from the second to the n-th. Therefore, the urging force that impels the side edge aligner and presses it against the side edges of the sheets is respectively and gradually increased in accordance with the distance traveled by the movable member.
Alternatively, the first to n-th load acting members are provided as first to n-th slots extending in a movable direction of the movable member, respectively. The first to n-th elastic members are tension springs, one ends of which are formed with hook members respectively hooked over the first to n-th slots with clearances L1, L2, . . . Ln, and the other ends of which are fixed to the first to n-th load application members.
Alternatively, the first to n-th load application members are provided as first to n-th application-side slots extending in a movable direction of the movable member, respectively. The first to n-th load acting members are provided as first to n-th acting-side slots extending in a movable direction of the movable member, respectively. The first to n-th elastic member are tension springs, one ends of which are formed with hook members respectively hooked over the first to n-th application-side slots, and the other ends of which are formed with hook members respectively hooked over the first to n-th acting-side slots. Additional clearances between the both hook members and the associated slots in the first to n-th elastic members are L1, L2, . . . Ln.
Preferably, the paper feeding device further comprises a cassette holder, to which the cassette member is detachably inserted. The movable member is moved such that only the first to n-th urging forces are added in order as a resultant urging force applied to the side edge aligner, then the n-th to first urging force is reduced in order from the resultant force.
In this configuration, an increasing load is gradually imposed by the first to the n-th elastic members, and the side edges of the sheets are aligned by the pressure applied by the side edge aligner. Then, the load imposed by the elastic members is gradually reduced. Thus, the pressure applied to the side edges of the sheets is reduced while the aligned state of the sheets is maintained and the resistance is reduced when a sheet is fed from the cassette member.